The present invention relates generally to signal processing circuits for binaural signals, and more particularly to a circuit capable of processing signals in such a manner that a signal having no localization information is converted to obtain binaural signals, and further, that a localization position of the sound image is shifted arbitrarily.
A so-called binaural system in which microphones are provided at the positions of the two ears of a dummy head having the shape of a human head to record the sounds respectively at the positions of the two ears, and the sounds obtained by reproducing these recorded sounds are respectively supplied to the headphone speakers for respective ears of a headphone set is known. By using this system, the listener can hear these sounds as though the position of the acoustic image were at the same position as that of the actual sound source.
In order to obtain this binaural signal, a dummy head must be used, heretofore. Accordingly, a signal processing circuit for obtaining signals substantially equivalent, electrically, to binaural signals from ordinary monaural signals or respective channel signals of stereo signals was devised. By the use of this signal processing circuit, substantially binaural signals can be obtained without the use of a dummy head.
However, the signal processing circuit of this type known heretofore is not able to shift the localization position of the sound image to a position where a listener intends to localize. In a system using the dummy head, for shifting the sound image, the sound source is required to move with respect to the dummy head, or the dummy head is required to move with respect to the sound source, whereby this moving operation is rather troublesome.